The Skylab space station was an outgrowth of numerous NASA and military studies of an orbital space station dating from the mid 1950s. In April 1966 contract work began on what would become Skylab. Design work continued over the next two years. Because of budget cuts, the Skylab program was cut back to only a single small low orbit unit. Skylab became the United States' first space station and it orbited from 1973 to 1979. It included a workshop and a solar observatory. Three manned missions to the station, launched in 1973 and 1974 using the Apollo Command / Service Module atop the Saturn IB each delivered a three astronaut crew. On the last two manned missions, an additional Apollo / Saturn IB stood by ready to rescue the crew in orbit if it was needed. Skylab was launched on May 14, 1973 by a modified Saturn V. Severe damage was sustained during launch and deployment, including the loss of the station's micrometeoroid shield / sun shade and one of its main solar panels. The other solar panel was also pinned into place. The first crew was able to save it in the first major space repair by deploying a replacement heat shade and freeing the jammed solar panels. Numerous scientific experiments were conducted aboard Skylab during its operational life, and crews were able to confirm the existence of coronal holes in the Sun. The Earth Resources Experiment Package (EREP) was used to view Earth with sensors that recorded data in the visible, infrared, and microwave spectral regions. Thousands of photographs of Earth were taken, and records for human time spent in orbit were broken. Plans were made to refurbish and reuse Skylab using the Space Shuttle to boost its orbit and repair it. However, development of the Shuttle was delayed, and Skylab reentered Earth's atmosphere and disintegrated in 1979, with debris striking portions of Western Australia.